Some electric machines operate to convert mechanical movement (e.g., kinetic energy) into electrical power, convert electrical power into mechanical movement, or both. For example, an electric machine system that operates to convert mechanical movement into electrical power (i.e., generate electrical power) can include an electric machine coupled to a companion device that is a prime mover. The prime mover supplies mechanical movement to the electric machine, which converts the mechanical movement into electrical power. An electric machine system configured to convert electrical power into mechanical movement (i.e., motor) can include an electric machine coupled to a companion device that is driven by the mechanical movement output from the electric machine. In certain instances, electric machine systems configured to both generate electrical power and mechanical movement can include an electric machine coupled to a companion device (e.g., a prime mover) that may be driven by the electric machine and that may drive the electric machine.